Today, the interest in developing and improving alternative lighting devices has greatly increased due to the removal of incandescent light bulbs on the market. This has further lead to increased demands on reduced production costs and to increase the performance of the alternative lighting devices. For example, lighting devices with light emitting diodes have several advantages compared to other conventional lighting, including for example high energy efficiency, high light output and long service life. Therefore, light emitting devices have also started to be incorporated into tubular lighting devices, replacing the traditional fluorescent tubes commonly found in offices, and other general places.
However, the use of light emitting diodes in general lighting is generally associated with problem relating to unsatisfactory illumination distribution, such as uneven light distribution, glaring light and spottiness. Persons exposed to this type of lighting may be affected negatively by for example being forced to peer or otherwise risk eye strain to compensate for the unsatisfactory illumination.
In US2012/0106144, a LED tube lamp is disclosed having an optical arrangement of lenses arranged to spread light from light emitting diodes to a cover in order to achieve a more uniform light output distribution.
However, it would be advantageous to provide a lighting device with an improved illumination distribution to fulfill the requirements of light output intensity and distribution in an alternative manner.
Hence, there is a further need for a lighting device adapted to be arranged in fluorescent lighting fixtures and luminaires to provide improved illumination distribution. Additionally, there is a further need for a lighting device for improved illumination distribution able to be provided by cost efficient components.